Merge branch 'maint-0.2.9' into maint-0.3.5

    ## We run basic tests on macOS

    - compiler: clang

      os: osx

      ## Turn off some newer features, turn on clang's -Wtypedef-redefinition

      env: C_DIALECT_OPTIONS="-std=gnu99"

    ## We check NSS

    ## NSS is a fast job, clang is slower on Linux, so we do NSS clang

    - env: NSS_OPTIONS="--enable-nss"

      compiler: clang

    ## We run chutney on Linux, because it's faster than chutney on macOS

    - env: CHUTNEY="yes" CHUTNEY_ALLOW_FAILURES="2" SKIP_MAKE_CHECK="yes"

    ## Use -std=gnu99 to turn off some newer features, and maybe turn on some

    ## extra gcc warnings?

    - env: CHUTNEY="yes" CHUTNEY_ALLOW_FAILURES="2" SKIP_MAKE_CHECK="yes" C_DIALECT_OPTIONS="-std=gnu99"

      ## (Linux only) Use an older Linux image (Ubuntu Trusty)

      ## The Xenial and Bionic images cause permissions issues for chutney,

      ## this is a workaround, until we fix #32240.

  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then export TOR_SKIP_TEST_REBIND=true; fi

  - ./autogen.sh

  - CONFIGURE_FLAGS="$ASCIIDOC_OPTIONS $COVERAGE_OPTIONS $HARDENING_OPTIONS $MODULES_OPTIONS $NSS_OPTIONS $OPENSSL_OPTIONS $RUST_OPTIONS --enable-fatal-warnings --disable-silent-rules"

  - echo "Configure flags are $CONFIGURE_FLAGS"

  - ./configure $CONFIGURE_FLAGS

  - echo "Configure flags are $CONFIGURE_FLAGS CC=\"$CC $C_DIALECT_OPTIONS\""

  - ./configure $CONFIGURE_FLAGS CC="$CC $C_DIALECT_OPTIONS"

  ## We run `make check` because that's what https://jenkins.torproject.org does.

  - if [[ "$SKIP_MAKE_CHECK" == "" ]]; then make check; fi

  - if [[ "$DISTCHECK" != "" ]]; then make distcheck DISTCHECK_CONFIGURE_FLAGS="$CONFIGURE_FLAGS"; fi

  o Testing:

    - Require C99 standards-conforming code in Travis CI, but allow GNU gcc

      extensions. Also activates clang's -Wtypedef-redefinition warnings.

      Build some jobs with -std=gnu99, and some jobs without.

      Closes ticket 32500.